Original article
Cardiovascular
Improved Mechanical Reliability of the HeartMate XVE Left Ventricular Assist System

https://doi.org/10.1016/j.athoracsur.2006.04.057Get rights and content

Background

The HeartMate XVE left ventricular assist device is a valuable treatment option for patients with end-stage heart failure. During the past several years, the XVE has undergone a series of design enhancements to improve reliability. We compared the reliability of the two most recent design iterations of the XVE pump (stitch modification to the inflow valve assembly and new inflow valve housing redesign) to the earlier VE version.

Methods

A retrospective evaluation of device reliability was performed for 268 devices implanted in 245 patients (VE: n = 167 devices, 147 patients, implant dates October 16, 1998, to December 19, 2003; XVE: n = 101 devices, 98 patients, implant dates August 1, 2002, to April 14, 2004).

Results

Median duration of device support for the VE and XVE was 159 days (range, 0 to 1,206 days) and 229 days (range, 0 to 693 days), respectively (p = 0.495). Significantly fewer major device malfunctions occurred within the XVE group as compared with the VE group (6 versus 36, respectively; p = 0.0003). The number of major device malfunctions per patient-year of support for inflow valve dysfunction, bearing wear, and other failures for the VE and XVE were 0.2 versus 0.04 (p = 0.006), 0.16 versus 0.01 (p = 0.005), and 0.06 versus 0.04 (p = 1.000), respectively. The freedom from major device malfunction at 1 year was 76% ± 6% for the VE and 97% ± 2% for the XVE device (p < 0.001). The freedom from death as a result of major device malfunction at 1 year was 97% ± 2% for the VE and 98% ± 2% for the XVE (p = 0.698).

Conclusions

Design enhancements to the HeartMate XVE have significantly reduced the incidence of major device malfunctions compared with the earlier VE model because of a reduction in failure modes from bearing wear and inlet valve dysfunction. Further follow-up is necessary to establish the long-term durability of the most recent XVE pump version.

Section snippets

Device

Incremental improvements were made to the current HeartMate XVE device in comparison with the previous HeartMate VE model. The first significant change was to the inflow valve assembly with the addition of sutures at the valve commissures to strengthen the attachment to the graft material, prevent valve dysfunction, and reduce the risk of disconnection (Fig 1). High pressure in the pump chamber would tend to displace the original valve and cause graft distortion. In addition, sutures that

Results

From September 28, 1998, through May 31, 2004, 147 patients underwent implantation of 167 HeartMate VE devices and 98 patients underwent implantation of 101 HeartMate XVE devices. There were no significant differences between groups with regard to age, sex, cause of the heart failure, percent of patients undergoing implantation for bridge to transplant indication, and volume of implants at each participating center (Table 1). The median duration of support for the VE was 159 days (range, 0 to

Comment

Data from this study demonstrate that important design modifications to the HeartMate XVE LVAD have resulted in a significantly decreased incidence of major device malfunctions. Importantly, significantly fewer major device malfunctions occurred with similar duration of device support between the groups. This decrease in incidence of major device malfunctions was primarily attributable to the significant reduction in incidence of both inflow valve dysfunction and bearing wear (either main

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